1. Field of the Invention
The present invention relates to a printer and, more particularly, it relates to a printer adapted to minimize the difference in the color tone and the contrast between an image displayed on a display device and a corresponding picture printed by the printer.
2. Prior Art
Conventionally, methods as described below have been popularly used to print a picture that may more often than not be a natural scene.
With a first method, a general purpose computer connected to a printer will also be connected to input devices for receiving image data and the image data read by the computer from each of the input devices are subjected to a predetermined processing operation to produce printing data, which printing data are then input to the printer in order to make the latter print an image on the basis of the printing data it receives. The input devices may include one or more than one removable medium drives, an NTSC (National Television System Committee) video signal input substrate, a silver salt film scanner and a digital still camera.
With a second method, input devices typically including a digital still camera and an original reader/scanner are directly connected to a printer without a general purpose computer interposed therebetween and printing data input through each on the input devices are applied to the printer in order to make the latter print an image on the basis of the printing data it receives.
Now, the first method will be discussed in greater detail. With this method, a system as illustrated in FIG. 1 of the accompanying drawings and principally comprising a host computer (hereinafter referred to simply as computer) 1001, a printer 1002 and an input device 1003 will be used.
The input device 1003 may be a removable medium drive (where the removable medium may be a read-only optical disk such as CD-ROM or a writable magneto-optical disk such as MD-DATA) drive, a video signal input device (where the video signal may be an NTSC signal, a PAL (Phase Alternation by Line) signal, an RGB signal or an S-terminal signal), a digital still camera, a silver salt photograph film scanner(where the film may be a 35 mm film or an ASP film containing magnetic data related to an image) or an original reader/scanner.
The printer 1002 may typically comprises a printing head 1004 for actually printing an image and a head drive circuit 1005 for driving the printing head 1004.
The computer 1001 may typically comprises an interface 1006 to be used for receiving image data by way of the input device 1003, a data processing section 1007 for processing the input image data as printing data and a bidirectional printer interface 1008 for outputting the printing data to the printer 1002. The data processing section 1007 is provided with a device driver adapted to control the operation of the input device 1003, a printer driver adapted to control the operation of the printer 1002 and application programs for controlling the operation of receiving and processing image data and that of outputting printing data. The data processing section 1007 is driven by the application programs to carry out its data processing operations.
On the other hand, the computer 1001 is typically provided with a display device 1009 operating as man-machine interface and a command device 1010 for externally entering a command such as a mouse or a keyboard. Additionally, said computer 1001 is also provided with an image memory 1011 such as a hard disk for storing the image data entered through the input device 1003.
Thus, all the above listed elements will be connected as the input device 1003 is connected to the interface 1006 in the computer 1001 and the bidirectional printer interface 1008 in the computer 1001 is connected to the printer 1002.
The operation of printing an image with the first method proceeds in a manner as described below. Firstly, the input device 1003 is driven to operate by way of the interface 1006 for entering image data by driving the application software of the computer 1001 and the device driver of the input device 1003 so that the entered image data will be read by the input device 1003 under the control of the computer 1001. Thus, the entered image data enter the computer 1001 by way of the interface 1006.
Then, the application software of the data processing section 1007 carries out an image editing/processing operation on the image data entered to the computer 1001 according to the command externally entered through the command device 1010 for the user. If the operation of processing the image data involves arithmetic operations, the data processing section 1007 in the computer 1001 also carries out necessary arithmetic operations in order to process the image data satisfactorily for the user.
Once the image editing/processing operation is carried out to the satisfaction of the user to define an image to be printed, the image will then be actually printed. More specifically, the application software carries out an operation of processing the data necessary for printing the image by means of the data processing section 1007, controlling the printer driver, in order to convert the data into printing data that can be accepted by the printer 1002. Note that the computer 1001 is aware of the condition of the printer 1002 as the latter is feedback to the computer 1001 by way of the bidirectional printer interface 1008.
The printing data obtained as a result of the above converting operation is designed to take the form of a printer control instruction and transmitted to the printer 1002 by way of the bidirectional printer interface 1008. Then, the printer 1002 drives the printing head 1004 by means of the head drive circuit 1005 according to the printing data contained in the printer control instruction it has received and prints the image on a recording medium.
FIG. 2 of the accompanying drawings schematically illustrates an arrangement that can be used to process the data in the above operation. In FIG. 2, the slashes on the lines indicating flows of data denote respective 8-bit/color data. The RGB image data input to the image data input section 1012 of the computer 1001 are then transmitted to the image data processing section 1013 and subjected to necessary processing operations there. If necessary, they will be retained in the image memory 1011 as image file 101 la. The RGB image data will then be transmitted from the image data processing section 1013 to the printer driver 1014 that controls the printer 1002.
The printer driver 1014 principally comprises an RGB-CMY converting section 1015 for converting RGB image data into CMY printing data, a color correcting section 1016 for carrying out necessary color correcting operations, a black extracting/underlying color removing section 1017, an output gamma correcting/tone modifying section 1018 and a sharpness modifying section 1019 adapted to process edges of the image.
Thus, the RGB image data transmitted from the image data processing section 1013 to the printer driver 1014 are firstly converted into CMY printing data and corrected for colors before they are converted into printing data containing data for black (printing data for black are denoted by K in FIG. 2), which data are then corrected for the characteristics specific to the printer and processed for edges. The obtained corrected data are then transmitted to the printer 1002. Note that, if the printer 1002 is a binary printer such as an ink jet printer adapted to reproduce the image as a function of presence of absence of each of a predetermined number of printing dots, a binarizing section will have to be arranged downstream relative to the sharpness modifying section 1019 of the printer driver 1014. On the other hand, the use of such a binarizing section will not be necessary if the printer 1002 is of a type adapted to express the tone of the image by means of the printing dots such as a sublimation type printer.
The printer 1002 comprises an output characteristics converting section 1020 for correcting the output characteristics of the printer and suppressing variances in the printed image attributable to the printer, a head drive circuit 1005 and a printing head 1004, which are already described above.
Thus, the CMYK printing data transmitted to the printing 1002 from the printer driver 1014 are sequentially fed to the head drive circuit 1005 and the printing head 1004 by way of the output characteristics converting section 1020 so that an image will actually be printed out.
Now, the second method will be discussed in greater detail. With this method, a system as illustrated in FIG. 3 of the accompanying drawings and principally comprising a digital still camera 1021 and a printer 1022 will be used.
The digital still camera 1021 principally comprises an image pickup section 1023 for picking up an image of an object, a command device 1024 for externally receiving commands for the operation of the shutter and so on, an image memory 1025 for temporarily storing the data on the picked up image, an image data processing section 1026 adapted to carry out necessary data processing operations and a display device 1027 for displaying the picked up image.
On the other hand, the printer 1022 comprises as principal components thereof an output characteristics converting circuit 1028 for correcting for correcting the output characteristics of the printer, a head drive circuit 1005 for driving the printing head 1030 and a printing head 1004 for actually printing images.
The digital still camera 1021 is connected to the printer 1022 by way of a wire so that the image data produced by the digital still camera 1021 may be transferred from it to the printer 1022 directly or after having been transformed into printing data in the form of digital signal or analog video signal obtained by transforming the digital signal. Alternatively, the image data may be transferred wirelessly typically by means of Ir-DA.
The operation of printing an image with the second method proceeds in a manner as described below. The image pickup section 1023 of the digital still camera 1021 takes in an image signal of the object to be shot in a ready state before the user actually depress the shutter to shoot the object and the image data processing section 1026 carries out certain correcting operations on the characteristics of the image pickup section 1023 and the shooting conditions for the image signal. Thus, an image obtained by carrying out the above correcting operations is displayed on the display 1027 so that the user can see the object to be photographed in the frame of the display device of the camera. If the display device 1027 is replaced or used with an optical viewfinder, the user can see the object to be photographed in the frame of the viewfinder.
As the user operates the command device 1024 that may be a shutter, the camera starts an image pickup operation. As the shutter is depressed to start the shooting operation, the image data taken in by the image pickup section 1023 and subjected to correcting operations on the characteristics of the image pickup section 1023 and shooting conditions by the image data processing section 1026 are stored in the image memory 1025. If necessary, the image data may additionally be subjected to data compression by the image data processing section 1026.
FIG. 4 of the accompanying drawings schematically illustrates an arrangement that can be used to process the data in the above operation. In FIG. 4, the slashes on the lines indicating flows of data denote respective 8-bit/color data. The RGB image data obtained by the image pickup section 1023 of the digital still camera 1021 are then transmitted to the image data processing section 1026 and subjected to necessary processing operations there. If necessary, they will be retained in the image memory 1025. The RGB image data will then be transmitted from the image data processing section 1026 to the printer 1022 by way of image data output section 1031.
The printer 1022 comprises components similar to that of the printer driver 1014 shown in FIG. 2 in addition to the above described output characteristics converting circuit 1028, the head drive circuit 1029 and the printing head 1030.
Thus, the printer 1022 comprises an image data input section 1032 for receiving image data from the digital still camera 1021, an RGB-CMY converting section 1033 connected to the image data input section 1032 to convert RGB image data into CMY printing data, a color correcting section 1034 for carrying out necessary color correcting operations, a black extracting/underlying color removing section 1035 (printing data for black are denoted by K in FIG. 4), an output gamma correcting/tone modifying section 10136 for correcting the characteristics specific to the printer and a sharpness modifying section 1037 adapted to process edges of the image.
Thus, the RGB image data input to the image data input section 1032 to the printer driver 1014 are firstly converted into CMY printing data and corrected for colors before they are converted into printing data containing data for black, which data are then corrected for the characteristics specific to the printer and processed for edges. The obtained corrected data are then transmitted to the output characteristics converting circuit 1028. Note that, if the printer 1022 is a binary printer such as an ink jet printer adapted to reproduce the image as a function of presence of absence of each of a predetermined number of printing dots, a binarizing section will have to be arranged downstream relative to the sharpness modifying section 1037. On the other hand, the use of such a binarizing section will not be necessary if the printer 1022 is of a type adapted to express the tone of the image by means of the printing dots such as a sublimation type printer.
Therefore, the CMYK printing data are transmitted sequentially to the head driver circuit 1029 and the printing head 1030 by way of the output characteristics converting circuit 1028 for printing an image.
However, the above described printing methods are accompanied by the following problems.
With the first method, various peripheral devices have to be arranged in place and connected to the computer and then device drivers adapted to the respective peripheral devices have to be incorporated into the computer. This is a very cumbersome operation. Additionally, application programs adapted to input, edit, process, correct and/or print images to the satisfaction of the user have to be installed into the computer. Then, the device drives have to be regulated in such a way that their respective application programs may properly control the respective peripheral devices to increase the cumbersomeness of operation. If one or more than one peripheral devices that cannot be controlled by the commercially available application programs are involved, additional application programs will have to be prepared for them. Then, the user will have to handle a number of application programs that have to be exchange image data. Thus, it will be appreciated that a tremendous degree of cumbersomeness will be involved in the above operation.
Additionally, if a desk-top type or tower-type computer is used, a large space will be require to connect it to the peripheral devices to give rise to a handling problem.
Furthermore, commercially available application programs are designed to operate multi-functionally in order to make them adaptable to marketed image input devices and printers that are normally designed to be as general purpose devices so that the user will have to give commands to select specific features of the programs probably. This sort of operation of selecting specific features of given programs normally is beyond the knowledge and skill of an ordinary user.
Conventionally, when displaying an image on a display device such as a CRT or a liquid crystal monitor and printing an image on a recording medium by means of a printer connected to a general purpose computer, the image data are corrected by the display device driver and the printer driver independently by taking the display characteristics and the printing characteristics into consideration respectively so that the reproduced image may be displayed and printed under optimal conditions.
However, with the above method of using a general purpose computer, it is generally not possible to specifically take the characteristics of the display device and those of the printer into consideration within the scope of the control ability of the operating system (OS) of the computer. This means that it is not possible to make the images displayed on the display screen of the display device and those printed by the printer have a uniform picture quality level regardless of the device and the printer connected to the general purpose computer and the quality of the image displayed on the display screen of the display device or printed by the printer is corrected optimally by the display device driver or the printer driver connected to the display device or the printer, which ever appropriate, according to the criteria of the driver. The net result can be that the picture quality of the image displayed on the display screen of the display device connected to the general purpose compression and that of the image printed by the printer connected to the general purpose computer do not necessarily agree with each other to a great disadvantage of the user.
Recently, color management systems have been developed. They have the objective of making image data input devices, display devices and printers to calorimetrically agree with each other. With such a system, the image data input through an input device are corrected in a manner specific to the device and the chromaticity coordinate system of the image data is converted to a standard one. Then, the image data expressed in terms of the standard chromaticity coordinates system are corrected in a manner specific to the display device that displays the image of the image data. Similarly, the image data are corrected in a manner specific to the printer that prints out the image of the image data. In this way, the related devices are made only to colorimetrically agree with each other under specific observing conditions (to be referred to as standard observing conditions).
Thus, with such a system, conditions other than the standard observing conditions are not taken into consideration. In other words, a system that is intended to have the related devices to calorimetrically agree with each other does not consider the remarkable aspect of the human nature that a person seeing same and identical images produced by different means of expression may have different impressions on them. This problem arises not only in terms of the image colors but also in terms of the sharpness of image and other aspects of image.
Thus, if the image data input to the different devices are corrected only in terms of the display output characteristics and the printing output characteristics independently to make them agree with each other calorimetrically, the person seeing the image produced by the display device and the image printed by the printer may normally have different impressions on them to produce a situation far from satisfying the observer.
With the above described second method, on the other hand, the achievement of operations of inputting, editing, processing, correcting and/or printing images exclusively relies on the functional features of the input device, which have only a limited capacity. Additionally, the performance of input device differs remarkably depending on the individual device and the operational procedures are often modified to a great disadvantage of the user. Additionally, it is currently not possible to use a film scanner for silver salts pictures as input device and technological developments are expected for printing copies of silver salt film pictures. Still additionally, the technological status quo is that an input device can be connected to a printer only to establish a one-to-one relationship and it is not possible to input image data concurrently through a plurality of input devices.
With the above described second method, the input device and the printer are functionally not related. In other words, the input device that is normally provided with an image display feature will be corrected in a manner suitable for its display output characteristics while the printer will be corrected in a way suited for its printing characteristics. As a result, the quality of the image displayed on the display device and the quality of the image printed by the printer do not necessary agree with each other.
In view of the above circumstances, it is therefore the object of the present invention to provide a printer that can be operated in a simple way without requiring a large space and with which difference in the color tone and the contrast between the image displayed on the display device and the image printed by the printer can be minimized to make the two images show visually a same quality.
According to the present invention, the above object and other objects of the invention are achieved by providing a printer comprising:
an image data input section adapted to convert the externally input digital image data and/or an analog image signal into first digital image data by analog/digital conversion;
an image printing correcting section for determining if each of the pixel data values found within a predetermined range of said first digital image data is found within a predetermined data range by means of a predetermined judging method and carrying out, whenever necessary, a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce second digital image data;
a printing output processing section for carrying out a printing output processing operation for converting said second digital image data into printing data for printing an image in an image printing section;
an image printing section for printing an image as output on a recording medium according to said printing data;
an image display output correcting section for determining if each of the pixel data values found within a predetermined range of said first digital image data is found within a predetermined data range by means of a predetermined judging method and carrying out, whenever necessary, a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce third digital image data; and
an image display output section for displaying said third digital image data as output;
said image printing correcting section being adapted to determine if each of the pixel data values found within a predetermined range of said first digital image data input by way of the image data input section is found within a predetermined data range and,
if it is determined that said pixel data values are not found within the predetermined range, carry out a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce second digital image data before sending them to the printing output processing section;
said image display output correcting section being adapted to determine if each of the pixel data values found within a predetermined range of said first digital image data input by way of the image data input section is found within a predetermined data range and,
if it is determined that said pixel data values are not found within the predetermined range, carry out a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce third digital image data before sending them to the image display output section.
As described above, in a printer according to the present invention, the image printing correcting section determines if each of the pixel data values found within a predetermined range of said first digital image data is found within a predetermined data range by means of a predetermined judging method and, if it is determined that said pixel data values are not found within the predetermined range, carries out a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce second digital image data before sending them to the printing output processing section, which then converts said second digital image data into printing data so that the image printing section prints out an image as output on a recording medium according to said printing data.
On the other hand, the image display output correcting section determines if each of the pixel data values found within a predetermined range of said first digital image data is found within a predetermined data range by means of a predetermined judging method and, if it is determined that said pixel data values are not found within the predetermined range, carries out a predetermined processing operation for making each of the pixel data values found within the predetermined range of said first digital image data found within a predetermined range to produce third digital image data before sending them to the image display output section, which displays said third digital image data as output.
Thus, with a printer according to the invention, the image printed by said image printing section and the image displayed by the image display output section are made to visually show a same quality by appropriately selecting a judging method and a processing method for the image printing correcting section and also appropriately selecting a judging method and a processing method for the image display output section.